Control apparatus



Feb. 29, 1944. M. E. WHITENACK CONTROL APPARATUS Filed May 27, 1942 INVENTOR- MIRL E. WHITENACK lu i; PM

ATTORNEYs Patented Feb. 29, 1944 CONTROL APPARATUS .Mirl E. Whitenack, Chicago, 111., assignor to Hurley Electronic-Controls, Inc., Chicago, Ill.,a corporation of Illinois Application'May 2'7, 1942, Serial N0. 444,740

8 Claims.

This invention-relates to control apparatus, and .has for its principal object to provide an improved control apparatus of "the character in which a Bourdon tube or equivalent pressuresensitive device is provided with a contact element mounted adjacent the free movable end thereof.

Various forms of apparatus in which aBourdon tube actuates a contact element have been proposed heretofore. Apparatus of this character heretofore proposed has not been of such design as to be capable of meeting the exacting require ments of modern sensitive electrical .control circuits. The apparatus provided by the present invention is of such design and construction as to be extremely accurate in its operation (within the limits of the Bourdon tube itself) and so provides an actuating mechanism for use in conjunction with modern electronic control circuits which possesses sensitivity commensurate with that of the control circuit.

Control apparatus according to the invention comprises a Bourdon tube having a contact element mounted thereon adjacent the closed movable end thereof, and advantageously in insulated relationship therewith. .A second adjustable contact element cooperates with the first contact element. Means for adjusting the position of the second contact element comprise a carriage on which said contact element is mounted, and ways in which said carriage may slide substantially along the path of travel of the contact element mounted. adjacent the end of the Bourdon tube. In addition, means are provided for sliding the carriage and the contact element thereon in the supporting ways to adjust the second contact element to a chosen position in the normal path of travel of the first-mentioned contact element. The substantially straight-line movement of the carriage carrying the adjustable contact element closely follows the path of travel of the contact element mounted adjacent the end of the Bourdon tube.

One of the contact elements (advantageously the one mounted on the Bourdon tube) preferably is formed with a contact surface which in crosssection taken substantially in the place of movement of the Bourdon tube is curved convexly toward the other contact element.

a plane substantially tangential to the curved contact element. This configuration of the contact elements insures that when the carriage is moved to follow the movement of the Bourdon tube, such movement of the two parts will be substantially proportional along substantially the full length of their paths of travel.

Preferably the apparatus also includes means for giving visual indication of the position of the carriage and the contact element thereon. Such The other contact element preferably is substantially flat in i tact element means comprise a pointer, and means connecting the pointer to the carriage in such manner as to move the pointer proportionally to movement of the carriage. To this end, a pointer may be pivotally mounted for movement through an angle at least approaching 360 to traverse an appropriate scale. A pinion connected to said pointer adjacent its axis of pivot engages with rack means. Linkage means connects the rack means to the carriage in such manner as to move the rack and thereby'to move the pointer proportionally to movement of the carriage.

The invention is described in greater detail below with particular reference to the accompanying drawing, in which Fig. 1 is a plan of apparatus constructed in accordance with the invention; and

Fig. 2 is an end view of the carriage assembly.

The apparatus shown in the drawing comprises a Bourdon tube l0 mounted by conventional mounting means H in a case l2. A suitable opening 13 is provided to admit a fluid under pressure to the open end of the Bourdon tube. At the closed end of this tube, there is mounted a contact element l4. The contact element l4 preferably is secured to and electrically insulated from the closed end of the Bourdon tube by an insulating block l5.

An adjustable contact element IE cooperates with the contact element M. The adjustable contact element 16 is securely mounted by a screw 11 on a carriage H1. The carriage is formed with grooves I9 (Fig. 2) for engagement with ways 20. The ways 20 are secured by screws or other means to the back of the case l2. The Ways 26 are mounted in such position as to be substantially parallel to the normal path of travel of the contact element l4. Consequently, the carriage I 8, in sliding in the ways 20, carries the contact element IS in a straight line along substantially the same path that is followed by the contact element l4, whereby these two contact elements are always in cooperating relation regardless of the adusted position of the carriage.

It will be noted that the contacting surface of the contact element I4 is of such configuration that, in a cross section taken substantially in the plane of movement of the free end of the Bourdon tube, it is curved convexly toward the contact element It. Such curvature may be secured by making the contacting portion of the element l4 spherical, hemispherical, cylindrical, semi-cylindrical, or of other appropriate shape. The con- IS mounted on the carriage is subin a plane substantially tangential surface of the contact element I4.

stantially flat to the curved In consequence of this configuration of the contact elements, any movement of the carriage fol the path of movement of the contact elelowing least a part of its length, and the threaded por tion enters into threaded engagement with a correspondingly threaded element 22 secured to the carriage. The free end of the sha'ft'Zl may be journaled in a bearing 23'at the end of the carriage to prevent even slight wabbling of the shaft. The shaft 2| extends outside the case l2, through a bearing 24 provided in suitable supporting block 25. A knob 26 secured to the end of the shaft outside the case is provided for turning the shaft. 1

In order to prevent axial movement of the shaft 2 a collar '21 is secured thereto'and bears against the end of the bearing 24' or other suitable sta-,

tionary member. A spring 28 is mounted in a recess in the block v'25. This spring, which is held under compression by a plate 29 secured to the block 25, presses the collar 2'! against the end of the bearing 24, and so prevents axial movement,

without allowing backlash, of the shaft 2!. I

By turning the knob 26, the carriage is caused to slide in its ways, therebycarrying the contact element It to a chosen position with respect to the contact element M. In order to secure a fine setting of the carriage 8 and the contact element l6 carried thereby, the threads on the shaft 26 may be fine, accurately cut micrometer threads.

, For the purpose of securing a visual indica:

tion of the setting of the carriage IS, a pointer 39 is provided. The pointer 30 is pivotally mounted by means of a shaft 3| approximately in the center of the case l2, and is arranged to traverse a scale 32 which advantageously extends almost completely around the periphery of the case I2.

arm about this pin will move the rack in such manner as to rotate the pointer about its pivot 3|. The curved end 3! of the arm. 35 is connected by a link 38 to the carriage l8, and is positioned above the adjustable contact element It as indicated by the dotted line across the tip of end 31 in Fig. 1. The link 38 is pivotally secured at one end to the end 31 of the rack arm, and is pivotally secured at its other end to the carriage. The pivot pins at each end of the link 38 may be adjustably secured in grooves or slots 39 and 40 in the arm 31 and the carriage l8, respectively, so as to permit adjustment of the position of the pointer relatively to the position of the carriage in initially setting or in calibrating the apparatus.

When the carriage is caused to slide in its ways, the rack 34 is moved by the link 38 to turn the pinion 33 and so to cause the pointer to traverse the scale. The scale may be graduated in whatever units (of pressure, temperature or the like) suit the use to which the apparatus is to be put. The magnitude in number of units of the scale graduations depends of course on the stillness of the Bourdon tube. which determines the magnitude of the forces in connection with which it is designed to be used.

In setting or calibrating the above-described apparatus, the pointer is set to read zero (or "other basic reference value) by suitable adjustment of the link 38 when the pressure in the Bourdon tube l0 corresponds to such basic reference value and the carriage is in such position that the contacts I4 and I6 are then barely touching. The scale is graduated in appropriate units corresponding to each unit increase (or decrease) of the pressure in the Bourdon tube. This graduation is advantageously carried substantially around the full 360 through which the pointer 39 may swing. Obviously the graduations may be carried to an extent greater or less than 360. At all points on the scale, however, the number of units indicated by the pointer corresponds to the position of the carriage when the contacts l4 and I6 are just barely touching with the pressure in the Bourdon tube corresponding to the indicated number of units.

In use, the contact elements I4 and i6 are connected to suitable electrical apparatus for controlling fiow, pressure, temperature or other factor to be controlled. For example, the contact elements may be suitably connected into an electronic control circuit such as is described in United States patent to Mirl E. Whitenack, No. 2,208,235, dated July 16, 1940. The Bourdon tube may be connected to a Vessel containing a fluid under pressure (or under vacuum), and the apparatus then may be used in controlling the pres sure of the fluid; or it may be connected to a fluid subjected to varying pressures corresponding to varyingrates of flow of a fluid through a conduit, in which case the apparatus may be used in controlling the rate of flow of such fluid; or the Bourdon tube may be filled with a thermally expansible fluid and may then be used in controlling the temperature of a body to which the thermally expansible fluid is exposed. Various other uses of the new apparatus will be apparent to those skilled in the art.

The new control apparatus is ofsuch design that it may be constructed to function with extreme accuracy (within the limits of accuracy of the Bourdon tube itself). The arrangement of the carriage l8, sliding in the Ways iii, along a substantially straight-line path, is such that the contact element carried by the carriage closely follows the normal path of travel of the contact element carried by the Bourdon tube. The curvature of the contacting surface of the contact element at the end of the Bourdon tube allows for angular movement of this contact during movement of the Bourdon tube without altering the effectiveness with which it makes contact with the cooperating contact element, and Without necessitating variation in the size of the unit graduations on the scale. At the same time the disadvantages of a point contact element are to the carriage to give a full 360 scale reading possesses obvious advantages in enabling the scale to be made large and easily read, and to permit of correspondingly fine adjustments in the seting of the carriage l8.

I claim: 1. Control apparatus of the character described comprising a Bourdon tube, a first contact element mounted thereon adjacent the closed movable end thereof whereby said contact element moves in a path similar to that of the moving end of said Bourdon tube, a second contact element cooperating with said first contact element, means for adjusting the position of said second contact element comprising a carriage on which said second contact element is mounted, ways in which said carriage may slide, said way being positioned substantially parallel to said path of movement of the first-mentioned contact element, means for sliding said carriage and the contact element thereon in said ways to adjust said second contact element to a chosen position in said path of movement of the first-mentioned contact element, and means including the configuration of said contact elements for maintaining the same proportional extent of movement of both of said contact elements at all contact positions of said elements along said path of movement.

2. Control apparatus of the character described comprising a Bourdon tube, a contact element mounted thereon adjacent the closed movable end thereof, a second contact element cooperating therewith, means for adjusting the position of said second contact element comprising a carriage on which said second contact element is mounted, ways in which said carriage may slide substantially along the path of travel of the first-mentioned contact element, and means for sliding said carriage and the contact element thereon in said ways to adjust said second contact element to a chosen position in the normal path of travel of the first-mentioned contact, and means for giving visual indication of the position of said carriage comprisin a pointer, and means connecting said pointer to said carriage in such manner as to move the pointer proportionally to movement of the carriage.

3. Control apparatus of the character described comprising a Bourdon tube, a contact element mounted thereon adjacent the closed movable end thereof in insulated relation therewith, a second contact element cooperating therewith, means for adjusting the position of said second contact element comprising a carriage on which said second contact element is mounted, Ways in which said carriage may slide substantially along the path of travel of the first-mentioned contact element, and means for sliding said carriage and the contact element thereon in said ways to adjust said second contact element to a chosen position in the normal path of travel of the firstmentioned contact, and means for giving visual indication of the position of said carriage comprising a pointer pivotally mounted for movement through an angle at least approaching 360, a pinion connected to said pointer adjacent its axis of pivot, rack means engaging said pinion, and a linkage connecting said rack to the carriage in such manner as to move the rack and thereby to move the pointer proportionally to movement of the carriage.

4. Control apparatus of the character described comprising a Bourdon tube, a contact element mounted thereon adjacent the closed movable end thereof, a second contact element cooperating therewith, and means for adjusting the position of said second contact element comprising a carriage on which said second contact element is mounted and movable substantially in the normal path of travel of the first-mentioned contact element, one of said contact elements having a contact surface which in cross-section taken substantially in the plane of movement of the Bourdon tube is curved convexly toward the other contact element, and the other of said contact elements having a contact surface which is substantially flat in a plane substantially tangential to the curved contact element.

5. In control apparatus comprising a Bourdon tube having a contact element mounted thereon adjacent the closed movable end thereof and an adjustable contact element cooperating therewith, the improvement which comprises forming one of said contact elements with a curved contacting surface which in cross section taken substantially in the plane of movement of the Bourdon tube is curved convexly toward the other contact element, and forming the other of said contact elements with a contacting surface which is substantially flat in a plane substantially tanential to the curved contact element.

6. In control apparatus comprising a Bourdon tube having a contact element mounted thereon adjacent the closed movable end thereof and an adjustable contact element cooperating therewith, means for supporting and adjusting the position of said adjustable contact element comprising ways arranged substantially parallel to the normal path of travel of the contact element mounted adjacent the closed end of the Bourdon tube, a carriage mounted in said ways and adapted to slide therein, means for mounting the adjustable contact element on said carriage, a shaft extending into threaded engagement with the carriage, and means preventing axial movement of said shaft, whereby rotation of said shaft imparts motion to the carriage in its supporting ways.

7. In control apparatus comprising a Bourdon tube having a contact element mounted thereon adjacent the closed movable end thereof and an adjustable contact element cooperating therewith, means for supporting and adjusting the position of said adjustable contact element comprising ways arranged substantially parallel to the normal path of travel of the contact element mounted adjacent the closed end of the Bourdon tube, a carriage mounted in said ways and adapted to slide therein, means for mounting the adjustable contact element on said carriage, a shaft extending into threaded engagement with the carriage, a collar on said shaft, a fixed bearing for engagement with said collar, and spring means pressing the collar against said fixed bearing to hold the shaft without backlash against axial movement, whereby rotation of said shaft imparts motion to the carriage in its supporting ways.

8. In control apparatus, the combination with a Bourdon tube having a moving contact mounted thereon adjacent the closed movable end thereof so as to follow a path similar to that of the moving end of said tube, and an adjustable contact cooperating with said moving contact and normally stationary with respect thereto, of means for adjusting said adjustable contact to move with respect to said moving contact substantially along said path followed by said moving contact, and means including a convex contact surface on one of said contacts and a substantially planar contact surface on the other of said contacts for maintaining a tangential relation between said contact surfaces at all contact positions of said contacts along said path.

MIRL E. WI-II'IENACK. 

